This invention relates to franking meter systems in which franking machines are utilized to frank postal items with a value of postage charge and in which funding of the franking machines with credit for use in franking is effected remotely.
Meters of franking machines for franking postal items and which are operated on a prepayment system are provided with a credit register which stores a value of credit for which payment has been made to a postal authority and which remains available for use in franking of mail items. Initially, upon payment to the postal authority, a value is entered into the credit register corresponding to the payment. As items are franked with postage charges, the value in the credit register is decremented by the postal charges and hence the decremented value represents the value remaining available for franking of postal items. When the value in the credit register has reduced to a predetermined value, which may be zero or a preset higher value, the accounting and control circuits of the franking meter prevent further franking operations until the user of the franking machine has purchased further credit from the postal authority and the value in the credit register has been incremented by the value of purchased credit. For reasons of security, the user of the machine is not permitted to have access to the interior of the franking meter or to any of the accounting circuits of the meter. According the addition of credit to the credit register is not permitted to be effected by the user of the machine. In known franking machines, the franking meter is a detachable module and when additional credit is to be entered in the meter the module is taken to the postal authority for resetting of the credit register. When the meter is returned to the postal authority for resetting the credit register, the postal authority is enabled to effect an auditing operation in which the contents of the credit register and other registers such as a tote register which records the total value of franking issued by the meter and an item counter which records the number of items franked by the meter are read. The auditing operation enables the postal authority to check usage of the machine as recorded by the various registers to ensure that the data in the registers is in agreement with usage of the machine since the preceding auditing.
The need to take the meter to a postal authority centre is inconvenient and time consuming to users of franking machines. The machine is not operable while the meter is removed for resetting and hence users need to anticipate their need for credit in order to prevent interruption to franking of mail items. In addition, the postal authority has to provide a resetting service at a large number of locations, for example at every main post office, in order to provide adequate accessibility of the service to customers.
In order to overcome the inconvenience of removing the meter and taking it to a postal authority resetting centre remote resetting systems have been proposed and are used. In one system, which is the subject of United Kingdom Patent No. 2173738, an electronic storage module is utilised to carry data between a postal authority resetting centre and franking machines at users locations. The module has credit data entered into and stored in it by the postal authority and after receipt thereof by the customer, the module is connected to the meter to enable the meter to read the credit data. The meter enters audit data into the module and upon return of the module to the postal authority, the postal authority reads the audit data and is enabled to carry out auditing of the usage of the meter. Thus the meter does not need to be removed from the franking machine and resetting is effected at the user's location. All data for the resetting of credit and auditing is carried by the module which is of sufficiently small size to be sent as a mail item between the user's location and the postal authority resetting centre. In order to provide security for the data transported in the module, the module also carries a code in the form of a pseudo-random number. This code is stored in the resetting computer and is written into the module together with the credit up-date value. The franking meter stores a code corresponding to that stored in the resetting computer. When the module is connected to the franking meter, the code in the module is compared with the code stored in the meter. If there is a match, the data in the module is accepted as valid. The code is changed after completion of each resetting transaction to prevent fraudulent resetting of the meter.
In another known system, resetting of the credit register of a franking meter is effected remotely by connecting the franking meter, by means of a modem, to the telephone network to provide direct communication with the resetting center computer. The procedure necessary for remote resetting of the register requires a sequence of messages to be passed between the franking meter and the resetting centre computer to enable the resetting centre computer not only to reset the credit value in the credit register but also to receive the accounting values stored in the other registers of the meter. If franking transactions were permitted to be carried out during the period in which the resetting procedure is taking place, accounting values stored in the registers of the franking meter would be changed in accordance with the postage value used in any franking transactions and accordingly auditing checks carried out to determine that the up-date credit value has been properly entered into the credit register and that the accounting data in other registers is in agreement could be indeterminate. Accordingly in a previously proposed system, which is the subject of U.S. Pat. No. 5,077,792, after initiation of the resetting procedure the resetting computer sends a message to the franking meter which locks and inhibits the franking machine from carrying out franking transactions. Upon completion of the resetting procedure after an audit of the register values of the franking meter has been satisfactorily carried out by the resetting computer the resetting computer sends an unlock message which permits the franking machine to carry out franking transactions. While this system is satisfactory with regard to preventing use of the franking machine while a resetting procedure is in progress it is considered that it may be disadvantageous in that if there is a failure in the resetting procedure due for example to equipment failure or a to failure in the communication link between the franking meter and the resetting centre computer the franking machine will remain locked and unavailable for use in franking mail items even though there is sufficient credit available in the credit register for franking further mail items.